Step 19: Plug it in and Hope for the Best

Step 20: Final Product

If you have made it through the instructable and now have a working timer either on the breadboard or on a PC board, congratulations! You have just pr...

The 555 timer. A chip so versatile that it has been used in everything from toys to spacecraft. A chip that can act as an oscillator, a schmitt trigger, PWM driver, a siren/alarm, a light or dark detector, and much much more. It is the most popular IC of all time having been around since 1971 and now selling over 1 billion annually.

This instructable will show you how to build your own 555 timer using only transistors and resistors, no ICs!

Why build this?
Good question. There are a few different reasons:
1. To Learn:
Learning may be a scary thought to some people, but this project has taught me a lot about comparators and analog circuits as well as a lot of the basics of the 555 timer. The 555 timer combines both digital and analog circuitry and while digital circuitry is taking over, analog is still important.
2. To Understand:
The 555 timer is a very versatile and useful chip. That's why it is the number 1 most produced chip. It is used very often so it is important to understand how the thing works. Now, you can read about it or even see a simulation, but nothing it quite as good as actually making it yourself.
3. It's Fun:
If you like working with electronics, especially breadboarded electronics, this should be a fun little project. You will break the black plastic barrier that stands between you and your integrated circuits and see the circuit in all its glory (well almost, making your own transistor could be difficult)!

Now that I've hopefully convinced you somewhere within that intro, lets get started!

This is an awesome tutorial! It took me a few days, but I was finally successful, after I realized a wiring mistake I made. I only did the breadboard version, I don't think I need to solder up the permanent version. I learned a lot, thanks!

Yes, exactly.The 555 is notorious for being very noisy, especially when the output changes. I threw the capacitor on it because there was room for it and so I didn't forget during testing. I must not have mentioned it anywhere in the instructable.

Hi! great work. I'm kind of new to electronics and started to experiment with building oscillators with the 555. my question is would an oscillator (for a synth) sound better with a discrete 555? Thank you!

It would make no real difference. The discrete 555 and an IC function the exact same way so it wouldn't matter. You would be better off using an IC because they are cheaper, easier to use, and don't take an hour of soldering to be ready to use.

The first thing I have to do is figure out how some of the elements can be implemented using tubes and how they would connect together. Actually building some circuits wouldn't be for a while but if you would be interested in supplying some triodes, I only have a few on hand and I know that I will need more. This should be a very cool project. I haven't worked with VTs other than with a guitar pedal.

I'm sure due to manufacturing constraints there is an upper physical limit to just how many components can be put on a die in a particular package but in practice there is very little relationship between the two characteristics. Something the examples you cited point out clearly. What is amazing about the 555, that you failed to mention, is that such a simple device has been so popular for so long.

What is more amazing is that many of the tasks the more complex micro-controllers are put to today could easily be accomplished using things as simple as the 555 is.

It does get smaller every year pretty much... We are fitting some 3 Billion transistors into a processor now (thats just average), but with Haswell and intel going down to 5nm production (hopefully by 2015!), we will see massive speed increases...

5nm by 2015 is pretty optimistic. There are physical limitations they've run up against at 22nm. Being as less than 22nm is shorter than the wavelength of light they use with masks to process dies. There are interference games they can play to get a little under that but I don't think the technique can be extended very far. I've heard of some 18nm stuff perhaps that is as low as they can go? The way the industry has been going lately I wouldn't hold my breath for any massive speed increases either. First off no one needs it, second there is no competition on the high end anymore to drive it.

The way forward seems to be parallelization, multicores and clustering. Maybe teaching kids how to program again.

If you are referring to historical computers then you should compare them to their peers now, which are physically large systems. The most powerful supercomputer today takes up 3,000 square feet of floor space, which is a square almost 55 feet on a side. Which is almost twice the physical size of ENIAC which was dubbed by the press a "Gigantic Brain".

Back then there really were no "our" computers so your comparison is basically flawed in that respect.

Really great instructable! I love building analog circuits from salvaged parts, and this project is right up my alley. You've done a fantastic job of breaking a complex subject into smaller more understandable components. Really well done.

Thanks!!! Digital has all but taken over electronics so I've been going analog!

I've been practicing breaking complex things down for a while now! None of my friends can bear more than 5 minutes of me talking about electronics unless I speak to them like they are 6 and my dad is a chemist so trying to communicate what I'm doing involves lots and lots of simplifying!

About This Instructable

Bio:I like to make things that move, sense, calculate, compute, blink, and make noise. I like making things that create high voltages, electrical arcs, and can light fluorescent bulbs at a distance. I li...read more »